By Gabriel Tan
The Cheetahs headed into Saturday evening's game at the Hougang Stadium holding a one-goal lead from the first leg, but were beaten 2-0 by the dominant visitors thanks to goals from Julien Durand and Hafiz Rahim.
And Bacina, who has long scoffed as suggestions of luck playing a part in football, believes the only reason why his side were knocked out is because they failed to deliver on the night.
"According to the way we played tonight [Saturday], we definitely didn't deserve to go through," the Croatian said. "I have to congratulate Gombak, they deserve to go through and I wish them all the best in the semi-finals.
"Of course I, as the coach, have to take the responsibility. For some reason, my players dropped back and let them press us and that's what cost us a goal.
"Maybe we couldn't handle the pressure and were not experienced enough for this situation, but hopefully we will learn from these mistakes."
Bacina was also puzzled with the way his players allowed Gombak to dominate proceedings, but was unwilling to use the absence of suspended star Jordan Webb, as an excuse for defeat.
"We proved when we played them in the first leg that we are able to keep possession well but somehow tonight [Saturday], we weren't able to do so," he added.
"I tried to convince my team that we are good enough to handle this game, but I have to say I wasn't successful.
"Of course, we were missing Jordan as he is a player who gives us courage up front. But we have to learn to deal with any missing players, even Jordan."
Gombak assistant coach Stephen Ng, who was taking charge of the side in the absence of K. Balagumaran, was effusive in his praise of the hunger his players displayed on the night.
"It was an impressive performance," Ng said. "I have to give it to the boys - they worked very hard today [Saturday].
"Although we have a game plan, it wouldn't work if the players don't apply it. They stuck to their tasks, we were very disciplined and I think it was one of Gombak's best performances this season."
Ng also believes the disappointment of Tuesday's first-leg loss, a game which they had led at halftime, spurred the Bulls on to make amends on Saturday.
"We lost the game at home and the boys were very disappointed then," he revealed. "We were very determined to come here and get the result.
"The hunger and desire we displayed were very strong."
Both sides are back in Great Eastern-YEO's S.League action next week, with Hougang looking to bounce back on Wednesday against basement club Geylang United, while Gombak will hope to continue their winning ways against Balestier Khalsa a day later.